Corrugating system employing controllable steam shower

ABSTRACT

The specification discloses a corrugating system comprising corrugating rolls for corrugating a sheet of paper as it is drawn from a roll of paper. Located between the corrugating rollers and the roll of paper is a steam shower which comprises a plurality of separate steam injection means extending across the width of the web of paper for injecting steam onto the sheet of paper as it is drawn from the roll to the corrugating rollers. Separate control means is provided for each steam injection means for separately controlling the injection of steam by each injection means to insure that the sheet of paper, as it leaves the steam shower, has an even distribution of moisture content along its width.

l l NOV. 25, 1975 l l CORRUGATING SYSTEM EMPLOYING CONTROLLABLE STEAM SHOWER [76] Inventor: William V. McDonald, 3l50 Hutchinson. Fort Worth, Tex. 76106 221 Filed: May 10, 1974 211 Appl. No.1468.807

3.676.247 7/l972 Morris ct ill. 264/286 X Primary Iiruminer-Robert L. Spicer. Jr. Alturmi. Agetll. 0r Firm-Arthur Fv Zohal {57] ABSTRACT The specification discloses a corrugating system comprising corrugating rolls for corrugating a sheet of paper as it is drawn from a roll of paper. Located hetwcen the corrugating rollers and the roll of paper is a steam shower which comprises a plurality of separate steam injection means extending across the width of the web of paper for injecting steam onto the sheet of paper as it is drawn from the roll to the corruguting rollers. Separate control means is provided for each steam injection means for separately controlling the injection of steam by each injection means to insure that the sheet of paper, as it leaves the steam shower.

has an even distribution of moisture content along its width.

7 Claims, 6 Drawing Figures DOUBLE HACKER U.S. Patent Nov. 25, 1975 Sheet 1 of2 3,922,129

CORRUGATING SYSTEM EMPLOYING CONTROLLABLE STEAM SHOWER BACKGROUND OF THE INVENTION This invention relates to a corrugating system for forming corrugated paper board and more particularly to a corrugating system employing a controllable steam shower which may be selectively controlled to control the moisture content across the width of the sheet of the paper being corrugated to prevent or minimize warpage.

Systems currently in use for forming corrugated paper board employ corrugating rollers for corrugating a sheet of paper drawn off ofa paper roll to form a corrugated layer. In order to facilitate corrugation and to insure that the corrugations formed retain their shape, one or more steam showers are employed to inject steam onto the sheet of paper upstream of the corrugating rollers. Sheets of paper are drawn from two other rolls and glued to opposite sides ofthe corrugated layer in separate stages in the process to form the desired paper board comprising a corrugated layer sandwiched between two liners. After the board is formed, it is passed through a heating and curing section to cure the glue and to dry the board. In many instances, however. the paper board produced is warped and hence cannot be used for its intended purpose. Warpage has been found to be due primarily to the fact that the roll of paper employed to form the corrugated layer is damp or moist in certain portions or strips along its width. After passage through the steam shower. the paper has an uneven moisture content across its width which results in uneven drying and hence warpage upon passage through the heating and curing section.

SUMMARY OF THE PRESENT INVENTION It is an object of the present invention to provide a system and method for use in a corrugating system for steaming in a controlled manner, a sheet of paper drawn from a roll prior to passage through corrugating rollers in order to prevent warpage of the paper board to be formed from the corrugated paper.

The system comprises a steam shower located between the roll of paper and the corrugating rollers and which comprises a plurality of separate steam injection means extending across the width of the sheet of the paper for injecting steam onto the sheet of paper as it is drawn from the roll to the corrugating rollers. Separate control means is provided for each steam injection means for separately controlling the injection of steam by each steam injection means. In one embodiment. the control means are manually controlled while in another embodiment, they are automatically controlled by a plurality of moisture detectors positioned across the width of the sheet of paper upstream of the steam shower. In the operation of the system employing the moisture detectors, as the sheet of paper is drawn from the roll, it is monitored for moisture content upstream of the steam shower. If a portion of the sheet of paper across its width upstream of the steam shower is found to have a moisture content above a predetermined level, there is terminated the injection of steam by said steam injection means which corresponds in position to the position of said moist portion of the sheet such that after the sheet passes over the steam shower. the sheet 2 will have an even distribution of moisture across its width.

In one aspect. the steam shower comprises a trough extending across the width of the sheet and having an open top end adapted to engage the bottom of the sheet as it is drawn from the roll to the corrugating rollers. The trough has a plurality of separate compartments along its length. each of which is open at the top end of the trough. A separate conduit extends into each compartment for separately injecting steam into each compartment for injection onto the portion of the sheet passing over each compartment as the sheet is drawn from the roll to the corrugating rollers. In addition. separate valve means is provided for each conduit for separately controlling the injection of steam into each compartment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a portion of a corrugating machine or system for forming corrugated paper board;

FIG. 2 is a perspective view of the steam shower of the present invention;

FIG. 3 is a perspective view of the steam shower of 4 FIG. 2 illustrating more details;

FIG. 4 is a cross-section of FIG. 3 taken through the lines 4-4 thereof;

FIG. 5 illustrates an embodiment which employs solenoid valves for controlling the flow of steam into the compartments of the steam shower; and

FIG. 6 is a plan view of the steam shower and illustrates another embodiment which employs sensors and a control system for automatically controlling the sole noid valves of the embodiment of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. I, there is illustrated a single facer for corrugating a sheet of paper or medium 2] drawn offofa roll 23 and bonding the corrugated paper to a liner 25 drawn off of another roll 27 to form a web 29 comprising the corrugated medium 21 bonded to the liner 25. The web 29 is fed to a double backer 3] which bonds another liner to the opposite side of the corrugated medium 21' to form the corrugated board 33 comprising the corrugated medium 21' having bonded to opposite sides liners 25 and 35. The corrugated board 33 is cut into sheets and then used to form boxes, etc. The conventional single facer comprises a support 4] for rotatably supporting the roll 23 and a support 43 for rotatably supporting the roll 27. In addition, there is provided a steam shower 45 comprising two conduits 47 and 49 extending across the width of the paper 21 on opposite sides for injecting wet steam evenly onto opposite sides of the sheet 21 as it passes between the shower members 47 and 49. The conduits 47 and 49 include a plurality of apertures or injection nozzles equally spaced along the lengths of the conduits for injecting an equal amount of steam onto the paper across its width as it passes between the conduits 47 and 49. Downstream of the steam shower 45 is a roller 51, a heated roller 53, a roller 55, and corrugating rollers 57 and 59. The paper 21 is passed through these corrugating rollers for corrugating the paper'to form the desired corrugations. A glue applicator roller 61 applies glue to the corrugated paper as it passes from between rollers 57 and 59. Roller 6l is located to be in contact with another roller 63 which is located to rotate in an elongated pan 65 containing glue 67. The paper 25 passes around roller 71 and between rollers 71 and 73. around roller 73 and then around roller 75 which is a heated pressure roller for pressing the paper sheet or liner against the corrugated medium 2] to bond the liner 25 to the corrugated medium 21' to form the desired web 29. Web 29 then is passed over a roller 76 and through two endless support belts 77 and 79 which are driven around rollers 77A, 77B, and 79A, 79B. Rollers S3. S7. 59, 71. 73, and 75 are heated rollcrs while rollers 53. S7, 59, 75. and belts 77 and 79 are driven by a drive arrangement not shown.

The double backer comprises additional heated rol Iers for drawing a liner off of another roll and for glue ing the liner to the opposite side of the corrugated medium 21. After the resulting board is formed. it is drawn through a curing section comprising two endless belts for drying the board. After drying. the board is cut into sections for its intended use.

In many instances. it has been found that the finished board sections are warped and hence not usable. From my investigation and observations, it has been found that the warpage is due primarily to the fact that the medium 2], which is a relatively porous medium. has moisture along certain strips or portions of its width. Upon passage through the conventional steam shower 45. steam is evenly injected along the width of the sheet 21 and hence the sheet has an uneven distribution of moisture along its width. The heated rollers evenly heat the corrugated paper. the web. and the board in the process along their widths and hence results in an uneven drying of the paper. resulting in warpage.

In accordance with my invention. 1 have eliminated the problem of warpage by employing a controllable steam shower 101 between the roll 23 and corrugating rollers 57 and 59.

Referring to FIGS. 24, the steam shower 101 comprises two elongated plates 103 and 105 connected together at right angles to form a trough which has two pie shaped end plates 107 and 109 connected to 0ppo site ends. Located in the trough between the ends 107 and 109 and attached to side plates 103 and 105 are a plurality of pie shaped dividers 1l1(1)l1l(l1) forming separate compartments 113(l)ll3( 12). It is to be understood that many more dividers may be employed forming many more compartments than those disclosed. The end plates 107 and 109 and the dividers 111(1 )lll(1 1) have curved top edges adapted to engage the bottom surface of the medium 21 as it is drawn from the roll 23. Rollers 115 and 117 hold the medium against the top edges of the end plates and the dividers of the open ended trough. Extending into each compartment and through the wall side 105 is a separate conduit coupled to a main steam flow conduit or manifold 115. The separate conduits connected to main conduit 115 are identified at l17(l)l17(12) in FIG. 3. These conduits extend through the wall 105 near its upper edge and hence extend into the separate compartments in their upstream ends. A wet steam source 119 is connected to one end of the manifold 115 for m jecting steam into the manifold and hence into the separate compartments by way of the separate and individual conduits 117(1)-1l7(l2). Each of the separate conduits 117(1)-1 17(12) has a control valve 121(1)l21(12) respectively for controlling the flow of steam into the various compartments. For purposes of clarity. the control valves 117(1)-ll7(12) are not illustrated in FIG. 2. but are illustrated in FIG. 3. These control valves are manually operated. however. they may be solenoid operated valves to allow the valves to be opened or closed remotely. as will be described sub sequently. A manually controlled valve 123 is located in the inlet of the manifold for on/off purposes while a manually controlled valve 125 is located in the line 115 downstream of steam conduit 117(12). The purpose of the valve 125 is to allow sufficient pressure to build up in line 115 yet to allow water. which condenses out of the steam in the manifold. to drain out through line 115. Each ofthe dividers 1l1(l)111(12) has its lower tip removed to form a space or slot at the apex of the walls 103 and 105 to allow water which condenses from the steam to drain out of the trough by way of a drain line 128. In FIG. 4. the bottom open space formed between the bottom of divider 111(6) and the apex of walls 103 and 105 is identified at 129. With the use of the present steam shower 10], the shower member 49 is removed but the shower 47 is retained. however. generally it will be shut off and used only in certain instances, for example. if it is known that the roll 23 is dry throughout.

In operation of the single facer with the use of the steam shower 101. the valves 12l[1)l2l(12) will be turned on or opened to allow the sheet 21 to be steamed as it passes over the shower. If. during the process. it is found that the board 33 is warped. it can be assumed generally that the warpage is due to the fact that the paper 21 had too much moisture along a certain strip as it comes off the roll 23. The warpage thus can be corrected by shutting off the the proper valves 12l(1)l21(12) which underlie the moist portion of the medium causing the warpage to terminate the injection of steam into their corresponding steam compart ments thereby terminating the steaming of the corresponding portion of the medium 21. Hence. as the me dium 21 passes the steam shower 101, it will have a more uniform moisture content across its entire width thereby allowing the paper and board to dry uniformly. hence preventing warpage.

In certain instances. it may be possible that warpage is due for example. to a given portion of the liner 25 being moist as it comes off of the roll 27. Correction of the warpage in this instance may be also carried out by terminating the injection of steam onto the medium 21 on the portion which will be bonded to the moist portion of the liner 25. Generally. however. warpage is due to too much moisture on a portion or strip of the medium 21 which is much more porous than the liner 25. thereby apparently resulting in inadequate drying in many instances, in the production process.

Referring now to FIG. 5. there will be described a modified embodiment, wherein the control valves 121( l )l21(12) are electromagnetic valves which can be turned on or off remotely. In FIG. 5, only one conduit 117(1) is illustrated. Its control valve is identified at 121(1). This valve is an electromagnetic valve employing a solenoid 131 for allowing the valve to be turned on or off remotely. In this respect. solenoid 131 has its two leads 131A and 1313 connected to conductors 135 and 137 which in turn are fed from an AC source 139. Lead 131A includes a manual onfoff switch 131C which normally is open. Valve 121(1) may be a spring biased valve which normally is biased in the open position whereby when switch 131C is open. the valve will allow the flow of steam through conduit 117(1). By closing switch 131C, coil 131 will be energized to close the valve 121(1). Each of the other solenoid valves I21(2)']2](12)' (not illustrated) employed to control the flow of steam through 5 the other conduits 117(2)1l7(12) are similar and their coils (not shown) are also connected to leads 135 and 137.

Referring to FIG. 6, there are illustrated a plurality of moisture sensors 141(1 )141( 12) which are employed to sense for or detect the moisture content of the paper medium 21 upstream of the shower 101 for automatically controlling the solenoid valves l2l(1)l21(12)'. The number of moisture sensors correspond in number to the number of compartments 113(1)113(12) and hence to the number of solenoid valves 121(1 )'-121( 1- 2). They are supported by a support means 143 above the medium 21 downstream of the roll 23 and are spaced across the width of the medium such that each will sense the moisture content along a strip which cor responds in position to the position of the compartment over which the strip will pass when it is pulled over the shower 101. The moisture sensors may be of the type manufactured by Moisture Register Company, 1510 West Chestnut Street, Alhambra, California. 9 I 802 but modified to be made relatively small. Moisture sensors or testers of this type comprise twin roller electrodes which are positioned to be in contact with the paper as it moves and includes circuitry for measuring the moisture by radio frequency determination of the dielectric properties of the paper. Instruments of this type test or sense by projecting a radio frequency field into the paper and measuring the loss as affected by the moisture. Moisture sensors of this type may be battery powered or may be powered by current obtained from a power source (not shown in FIG. 6). Each of the sensors include a meter 151 which may be used to obtain a moisture reading by direct observation. In the present system, the support 143 will support the moisture sensors such that their roller electrodes will be in contact with the top side of the paper medium 21 as it is unwound from the roll 23. The support 143 and hence the moisture sensors may be located relatively close to the upstream side of the steam shower 101 such that their roller electrodes always will be in contact with the top side of the medium 21 even as the diameter of the roll 23 decreases due to unwinding. If the moisture sensors are located further upstream and closer to the roll 23, an arrangement (not shown) may be provided for lowering the support 143 and hence the moisture sensors as the diameter of the roll 23 decreases due to unwinding to insure that the roller electrodes are continually maintained in contact with the top side of the medium 21. Each of the sensors has circuitry coupled to its corresponding solenoid coil of the solenoid controlled valves l21(1)'121(12) to automatically control its solenoid valve for automatically controlling the flow of steam into the corresponding compartment. In FIG. 6, the connection between sensor 141(1) and the solenoid 131 of valve 121(1) is illustrated. As shown in FIG. 6, leads 153 and 155 extend from the sensor 141(1) to circuitry 157 which in turn is coupled across the normally open switch 131C by way ofleads 159 and 161. Switch 163 normally will be closed. The circuitry 157 comprises a threshold device which operates a normally open electronic switch, included in circuitry 157, to electronically control the flow of current through solenoid 131. In operation, in the event that the sensor 141(1) senses moisture above the threshold as set by the circuitry 157, the electronic switch will close to allow current to flow through coil 131 thereby closing the valve 121(1). The flow of current from lead 137 may be traced by way of conductor 131A, conductor 159, closed switch 163, the closed electronic switch in circuitry 157, conductor 161, coil 13] and to lead 135 by way of conductor 1318. Each of the other sensors 114(2)-1l4(12l is coupled to the solenoid coil of its corresponding solenoid valve 121(2)121(12)' re spectivcly in a similar manner to automatically shutoff its solenoid valve in the event that the moisture level it senses is above the threshold level as set by its corresponding circuitry 157.

With the arrangement shown in FIG. 6, the automatic operations may be overridden by opening all of the switches 163 to allow manual switches 131C to be employed for control purposes. This may be desired to compensate for warpage due to moisture occurring on the liner 25. In addition, manual control may be employed, if desired, to manually control the solenoid valves 121(1)'121(12)' in accordance with the moisture content of the paper medium 21 as read from the meters 151.

In one embodiment, the dividers 111 employed in the trough 101 are spaced about 2 inches apart. The trough 101 and hence the plates 103 and 105 may have a length of about 87 inches. With a trough of this length,

- many more dividers 111 and hence many more compartments will be employed in the trough than shown in FIGS. 2 and 3. The plates 103 and 105 each may have a width of about 6 inches. The moisture sensors each will be small enough to sense for moisture along a strip which corresponds in width to the strip of paper which will pass over the compartments formed by the dividers 111. As shown in FIGS. 2 and 3, the dividers on each side of the center divider 111(6) angle outward from the upstream side of the trough to the downstream side. This arrangement maintains the paper smooth and prevents wrinkles as it passes over the steam shower 101. In one embodiment, the downstream end of each of the dividers at the top edge of plate 103 on each side of the center divider, may be located about one-half of an inch outward from their upstream ends, as measured from the top edge of plate 105.

I claim:

1. A corrugating system comprising:

support means for supporting a roll of paper,

corrugating rollers for corrugating a sheet of paper as it is drawn from the roll,

a steam shower located between said support means and said corrugating rollers and comprising a plurality of separate steam injection means located across the width of the sheet of paper for injecting steam onto the sheet of paper as it is drawn from the roll to the corrugating rollers,

a source of steam,

means for supplying steam to said steam shower,

a plurality of moisture detecting means corresponding in number to the number of said separate steam injection means,

said plurality of moisture detecting means being located upstream of said steam shower and across the width of the sheet of paper to detect for moisture in the sheet of paper across its width as the sheet of paper is drawn from said roll,

each moisture detecting means being located to correspond in position, across the width of the paper. to the position of one of said separate steam injection means, and

control means coupled between each moisture detecting means and its corresponding steam injection means for separately controlling each of said 7 steam injection means if the moisture detected exceeds a predetermined level.

2. A corrugating system comprising:

support means for supporting a roll of paper.

corrugating rollers for corrugating a sheet of paper as it is drawn from the roll,

a steam shower located between said support means and said corrugating rollers and comprising a plu rality of separate steam injection means located across the width of the sheet of paper for injecting steam onto the sheet of paper as it is drawn from the roll to the corrugating roller.

a source of steam.

means for supplying steam to said steam shower, and

separate control means for each steam injection means for separately controlling the injection of steam by the steam injection means said steam shower comprising:

a trough having a length extending across the width of the sheet of paper to be drawn from the roll,

said trough comprising a closed bottom end and an open top end adapted to engage the bottom of the sheet as it is drawn from the roll to the corrugating rollers.

said trough having a plurality of separate compartments along its length, each of which is open at the top end of said trough.

a separate conduit extending into each compartment for separately injecting steam into each compartment for injection onto the portion of the sheet of paper passing over each compartment as the sheet of paper is drawn from the roll to the corrugating rollers. and

separate valve means for each conduit for separately controlling the injection of steam into each compartment.

3. The system of claim 2 wherein said trough comprises:

two elongated side walls extending across the width of the sheet of paper to be drawn from the roll.

one side being defined as the upstream side located closer to the roll and the opposite side being defined as the downstream side and which is located closer to the corrugating rollers,

said compartments being formed by dividing walls extending across said side walls.

said dividing walls being positioned to angle outward on each side of the midpoint of said trough from the upstream side to the downstream side.

4. The trough of claim 3 wherein:

said separate conduits extend into each of said compartments on the upstream side of said trough.

5. The system of claim 3 wherein said separate valve means comprise manually controllable valve means.

6. The system of claim 3 wherein said separate valve means comprise solenoid controlled valves.

7. The system of claim 2 comprising:

a plurality of moisture detecting means corresponding in number to the number of said separate compartments of said trough and hence in number to the number of said valve means,

said plurality of moisture detecting means being located upstream of said steam shower and across the width of the sheets of paper to detect for moisture in the sheet of paper across its width as the sheet of paper is drawn from said roll,

each moisture detecting means being located to correspond in position, across the width of the paper, to the position of one of said compartments, and

control means coupled between each moisture de tecting means and its corresponding valve means for closing said valve means if the moisture detected exceeds a predetermined level.

* i t I 

1. A corrugating system comprising: support means for supporting a roll of paper, corrugating rollers for corrugating a sheet of paper as it is drawn from the roll, a steam shower located between said support means and said corrugating rollers and comprising a plurality of separate steam injection means located across the width of the sheet of paper for injecting steam onto the sheet of paper as it is drawn from the roll to the corrugating rollers, a source of steam, means for supplying steam to said steam shower, a plurality of moisture detecting means corresponding in number to the number of said separate steam injection means, said plurality of moisture detecting means being located upstream of said steam shower and across the width of the sheet of paper to detect for moisture in the sheet of paper across its width as the sheet of paper is drawn from said roll, each moisture detecting means being located to correspond in position, across the width of the paper, to the position of one of said separate steam injection means, and control means coupled between each moisture detecting means and its corresponding steam injection means for separately controlling each of said steam injection means if the moisture detected exceeds a predetermined level.
 2. A corrugating system comprising: support means for supporting a roll of paper, corrugating rollers for corrugating a sheet of paper as it is drawn from the roll, a steam shower located between said support means and said corrugating rollers and comprising a plurality of separate steam injection means located across the width of the sheet of paper for injecting steam onto the sheet of paper as it is drawn from the roll to the corrugating roller, a source of steam, means for supplying steam to said steam shower, and separate control means for each steam injection means for separately controlling the injection of steam by the steam injection means said steam shower comprising: a trough having a length extending across the width of the sheet of paper to be drawn from the roll, said trough comprising a closed bottom end and an open top end adapted to engage the bottom of the sheet as it is drawn from the roll to the corrugating rollers, said trough having a plurality of separate compartments along its length, each of which is open at the top end of said trough, a separate conduit extending into each compartment for separately injecting steam into each compartment for injection onto the portion of the sheet of paper passing over each compartment as the sheet of paper is drawn from the roll to the corrugating rollers, and separate valve means for each conduit for separately controlling the injection of steam into each compartment.
 3. The system of claim 2 wherein said trough comprises: two elongated side walls extending across the width of the sheet of paper to be drawn from the roll, one side being defined as the upstream side located closer to the roll and the opposite side being defined as the downstream side and which is located closer tO the corrugating rollers, said compartments being formed by dividing walls extending across said side walls, said dividing walls being positioned to angle outward on each side of the midpoint of said trough from the upstream side to the downstream side.
 4. The trough of claim 3 wherein: said separate conduits extend into each of said compartments on the upstream side of said trough.
 5. The system of claim 3 wherein said separate valve means comprise manually controllable valve means.
 6. The system of claim 3 wherein said separate valve means comprise solenoid controlled valves.
 7. The system of claim 2 comprising: a plurality of moisture detecting means corresponding in number to the number of said separate compartments of said trough and hence in number to the number of said valve means, said plurality of moisture detecting means being located upstream of said steam shower and across the width of the sheets of paper to detect for moisture in the sheet of paper across its width as the sheet of paper is drawn from said roll, each moisture detecting means being located to correspond in position, across the width of the paper, to the position of one of said compartments, and control means coupled between each moisture detecting means and its corresponding valve means for closing said valve means if the moisture detected exceeds a predetermined level. 